This fixes the standalone 64-bit Debug build.

Change-Id: I348b71a96ada435867367e565bc84b570d2bfb67
Reviewed-on: https://chromium-review.googlesource.com/204292Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>